At every step of the way it becomes slightly more acceptable to push the boundaries just so slightly.
[1] Been the case for many decades now in the case of sickle-cell anaemia, this affects partner selection. In the last decade selection against mutations in BRCA1 and BRCA2 i.e the "breast cancer genes", has lead to searches for egg donors. Also, some people with history of severe depression that runs in the family are self selecting against child bearing (this selection is more common among females).
[2] This could even be pseudo-science at the beginning.
[3] Sperm and egg banks already allow for a crude version of this.
[4] Either natural or synthetic.
I'm not a biologist, but reading this sounds more like a few years till mass market, not the ominous "30 years" you hear when people really have no clue how long it's going to take :-)